Pressure-actuated valve.



G. H. GILMAN.

PRESSURE ACTUATED VALVE- APPLICATION FILED FEB. 10. 1913.

Patented Dec. 14, 1915.

GEORGE E. GILMAN, 0F CLAREMONT, NEW HAMPSHIRE, ASSIGNOlR, BY MESNJH ASSIGNMENTS, T0 SULLIVAN MACHINERY COMPANY, 013' BOSTON, MASSACHU- SETTS, A CORIPORATION OF MASSACHUSETTS.

PRESSURE-ACTUATED VALVE.

Specification of Letters Patent. patt D 14, myg

Application filedfltebruary'm, 1913. Serial No. 747,295.

valves and more particularly to valves intended for direct-acting engines, such as are employed in connection with rock drilling machines.

The invention will be best understood byreference to the following description when taken in connection with the accompanying plied to a drill; Fig. 2 is a plan view of a portion of the cylinder'showing the relation of the portsyand Fig. 3 is a section on the line 33 of Fig. l.

Referring to the drawings and to the embodiment of my invention therein shown, I have illustrated the same as applied to a rock drilling engine having the cylinder 1, the piston 2, the latter having a contracted portion 3 between its ends which forms an annular chamber around the piston. This chamber may be provided with 'a vent 4. The piston rod 5 secured to the piston projects through the front head 6 and is attach- .ed to the drill bit, not herein shown.

The cylinder is provided with inlet. ports 7-and 8, the former leading to the forward end of the cylinder and the latter to the rearward end thereof. It is also provided with valve-reversing ports 9 and 10 which lead to opposite ends of the valve chamber, as will be more fully explained.

The valve chest 11 is provided with ports .12 and 13 which communicate respectively 19 and the exhaust passage 20. The valve chest is provided with the valve chamber 21 which receives the'piston valve 22, the latter gigving the opposite piston heads 24 and the intermediate but larger piston head 26. The opposite ends of the valve chamber are closed by the buffers 27 It will be observed that the inlet port 7, which leads to the forward end of the cylinder, communicates with the valve cham her at the rear of the piston head 26, while the inlet port 8, which leads to the rearward end of the cylinder, communicates with the valve at the forward side of the piston head 26. This brings the inlet ports 7 and 8 into crossed relation. It will also be observed that the reversing ports 9 and 10 do not have this crossed relation, but lead directly to the cylinder port 9, which opens at the rearward end of the valve chamber communicating with the rearward end of the main cylinder and the port 10 which communicates with the forward end of the valve chamber leading to the forward end of the cylinder.

The operation of the valve is as follows: In theposition shown, pressure fluid is being admitted from the admission passage 16 through the port 15 to the admission port 14. From here it passes through the valve chamber to the admission port 8,

passing into the rear of the cylinder and acting to drive thepiston forward. During this movement of the piston the valve is heldin the assigned position by the pressure of the admission fluid acting against the larger piston'26 of the valve, the rear end of the valve chamber being vented through the port 9 and the vent opening 4. Meanwhile pressure fiuid is exhausted from the forward end of the cylinder through the port 7, valve chamber port 12, ports 1719 and passage 20. This condition holds until the rear edge of the piston has passed the port 9, whereupon tpressure fluid isadmitted and 28, respectively.

- -specti\"ely.

reverse ports so that the ports may lead disleeve 29 which is cut' away to provide access to the pofts 13 and 18. In the reverse position of the valve, also the latter is held by admission pressure acting against the rear face of the larger piston head 26, and

the forward end of the valve chamber soon becomes vented through the port 10 after the same has been'opened to the annular space surrounding the contracted portion of the piston 3. Thus the pltessure of the actuating fluid which enters through the port 1% holds the valve against the one or the other of the two buffers until the piston has passed the reverse port so that unless the reverse porthas been opened the valve port cannotbe accidentally thrown or displaced.

Heretofore it has been customary to reverse the valve by means of reverse ports which connect the forward and rearward ends of the valve chamber with the rearward and forward ends of the cylinder re- By so arranging the inlet and rectly to the cylinder and connect the rearward and forward portions of the valve chamber with the rearward and forward portions of the vcylinder, respectively, a quicker action is secured for the reversing valve.

vWhile I have herein shown and described a for purposes of illustration one specific form of the invention, it is to be nmlerstood that the same IS not limited to the details of ports or the relative arrangement of the.

cylinder having reversing ports in the forward and rearward portions thereof leading to the forward and rearward ends respectively of said piston valve, means for admitting pressur in alternation to said reversing ports at each stroke of the piston,

sure. areas, said intermediate'n'icmbcrs ])l't% senting greater areas than either of the end ones. said cylinder having inlet ports for the forward. and rearward end thereof communicating with the valve chamber rcspcctivel-y at the rearward and forward ends of said member of greater area and having also reversing ports in the upper and lower portions thereof leading to the lower and upper ends respectively of said piston valve, -ach reversing port in the cylinder being adapted to be uncovered by the corresponding piston head first ononc side thereof and then on the opposite side and means for venting the chamber surronmling the intcrmediate portion of the piston whereby said piston valve is unbalanced when the piston passes the reversing ports.

in testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

lEOR-GF, ll. (lILMA .i.

Witnesses: Y

Rom-arr ll. RAMMLER, l. lnnsn CHANDLER. 

